Docs are missing from datasets when one of the node is failed over with cbas replica enabled

Testcase name -

test_cbas_node_crash_while_swap_rebalancing_cbas_nodes_does_not_change_actual_number_of_replicas

Steps to reproduce -

1. Have a 3 node cluster with following services -
   1. Node 1 - KV, N1ql, index
   2. Node 2 - CBAS
   3. Node 3 - CBAS
2. Create datasets, dataverses, indexes and synonyms.
3. set cbas replica to 2.
4. Now swap rebalance cbas nodes.
5. Stop couchbase-server on incoming node, such that rebalance started in step 3 fails.
6. restart the couchbase-server on incoming node.
7. rebalance again and wait for rebalance to finish (now we have 3 cbas node, so 2 replicas are now supported)
8. disconnect all the local links
9. mark one of the CBAS node as failed over, such that replica becomes active.
10. Now verify the doc count in the datasets created in step 2.

Few Docs in one of the datasets is missing.

This issue is intermittent.